Shubnikov-de Haas and de Haas-van Alphen effects have been measured in the underdoped high temperature superconductor YBa2Cu3O6.51. Data are in agreement with the standard Lifshitz-Kosevitch theory, which confirms the presence of a coherent Fermi surface in the ground state of underdoped cuprates. A low frequency F=530±10 T is reported in both measurements, pointing to small Fermi pocket, which corresponds to 2% of the first Brillouin zone area only. This low value is in sharp contrast with that of overdoped Tl2Ba2CuO6+δ, where a high frequency F=18 kT has been recently reported and corresponds to a large hole cylinder in agreement with band structure calculations. These results point to a radical change in the topology of the Fermi surface on opposing sides of the cuprate phase diagram.
@article{arxiv.1001.1508,
title = {Quantum oscillations in underdoped YBa_2Cu_3O_6.5},
author = {Cyril Jaudet and Julien Levallois and Alain Audouard and David Vignolles and Baptiste Vignolle and Ruixing Liang and D. A. Bonn and W. N. Hardy and N. E. Hussey and Louis Taillefer and Cyril Proust},
journal= {arXiv preprint arXiv:1001.1508},
year = {2015}
}